Backcoating

This is not backcoating as Yoshizawa does it, but is something that I
developed based on an article written by Toshi Aoyagi. The formal
Yoshizawa method of backcoating is much more involved.

For backcoating, you will need mulberry (kozo fibre) paper (or
another type of Japanese handmade paper, washi), a large flat surface to work on,
paste, and a brush. There are now cheaper machine-made substitutes to
washi such as the Thai unryu. In fact, for the beginner, I
would recommend unryu as it is cheaper and is easy to work
with.

The paste should be one that will integrate with the fibres of the
paper such as methyl cellulose (wallpaper paste), wheat starch paste
(sho fu), or rice starch paste. Yoshizawa uses sho fu, but I
recommend methyl cellulose as it is easier to use. You can buy pure methyl
cellulose at some art supply stores, at paper-making supply stores, and at
book-binding supply stores. Otherwise, standard wallpaper paste is mainly
methyl cellulose with some preservatives included (e.g. Methylan
Cellulose).

Cut the two pieces of paper to approximately the size you wish,
allowing a little extra paper along each edge so that you can trim it to
exact size after the paper dries.

Lay out the first sheet of paper on the flat surface. This first sheet
will take on the texture of the surface that you are working on. I prefer
to work on glass, but I usually use plexiglass (easier to handle). Metal
also works well. Polished wood will give a slight wood-grain texture.

Brush an even coat of paste onto it. The paste should be the
consistency raw egg white. Make sure you have no bubbles in the paper. The
paste will soak into the paper, and the paper will adhere to the flat
surface.

Carefully lay the second sheet over top of the first sheet. Starting
at one end, smooth the second sheet onto the first sheet with the brush.
Work carefully to avoid tearing the paper and to avoid wrinkles. If you
are fortunate enough to have someone to help you, they can hold onto the
opposite end of the second sheet from where you are working, keeping the
sheet taut and slightly above the first sheet, while you brush it down
onto the first sheet.

Let the sheet dry. You can speed up the drying process by using an
electric fan to blow on it. Avoid using heat, as the paper will dry at
different rates, causing a buckling of the paper, resulting in a warped
product. (Thanks to Courtney Spooner and Mette Pederson for this insight.)
If warping is not a concern for you, try peeling the paper off before it
has dried, and hang it up to dry. This will allow the paper to dry without
taking on the texture of your working surface.